Method for producing 2,2,2-trifluoroethanol

ABSTRACT

A method for producing 2,2,2-trifluoroethanol in which a γ-hydroxybutyric acid salt is reacted with 1,1,1-trifluoro-2-chloroethane to generate 2,2,2-trifluoroethanol is provided. This method leads to increased yields of 2,2,2 -trifluoroethanol, facilitates the separation of salt byproducts and allows the recycling of an aprotic polar solvent. 
     The present invention concerns a method for producing 2,2,2-trifluoroethanol in which a γ-hydroxybutyric acid salt is reacted with 1,1,1-trifluoro-2-chloroethane in an aprotic polar solvent to generate 2,2,2-trifluoroethanol. This method is characterized in that the γ-hydroxybutyric acid salt used contains no more than 6 wt % of 4,4′-oxybis(butyric acid).

This is a 371 of PCT/JP02/09402 filed Sep. 13, 2002, and published asWO03/024906 on Mar. 27, 2003.

TECHNICAL FIELD

The present invention relates to an improved method for producing2,2,2-trifluoroethanol, in which a salt of γ-hydroxybutyric acid isreacted with 1,1,1-trifluoro-2-chloroethane to produce the desiredproduct. The present invention further relates to a method for producinga salt of γ-hydroxybutyric acid to serve as a material for2,2,2-trifluoroethanol, as well as to a method for producing2,2,2-trifluoroethanol by recycling the γ-butyrolactone collected afterthe reaction.

BACKGROUND ART

Being salts of a hydroxyl-containing organic acid, γ-hydroxybutyric acidsalts can partially dissolve in organic solvents. For this reason,γ-hydroxybutyric acid salts are used to hydrolyze organic halides, suchas those having alkyl group, alkenyl group, allyl group and otherorganic functional groups, and serve as a useful reaction reagent toderive corresponding esters and alcohol derivatives.

γ-hydroxybutyric acid salts can be readily obtained by reactingγ-butyrolactone with a hydroxide or a carbonate of an alkali metal or analkaline earth metal. Since this reaction is generally performed in thepresence of water, γ-hydroxybutyric acid salts are obtained as aqueoussolutions. To make such solutions usable in reactions such as hydrolysisor esterification, the solutions must be dehydrated to adjust waterconcentration. This, however, often results in the formation ofcrystallized γ-hydroxybutyric acid salts. For this reason, a properaprotic solvent always needs to be selected and used in the reaction.

When an aqueous solution of a γ-hydroxybutyric acid salt is dehydrated,a 4,4′-oxybis(butyric acid) salt, which is an ether dicarboxylic acidformed as a result of the dehydration and subsequent dimerization, isgenerated as a byproduct (4,4′-oxybis(butyric acid) and its metal saltsmay be referred to as EDCA and EDCAM, hereinafter). For example, GermanPatent No. 919167 describes that EDCA is generated at 50 to 55% yieldsby mixing γ-butyrolactone with a hydroxide of an alkali metal or analkaline earth metal at 120 to 130° C., then heating the mixture at 180to 230° C. in the presence of aluminum oxide, and then dehydrating themixture for 8 to 10 hours. The German patent also describes that EDCA isgenerated at similar yields even in the absence of aluminum oxidewhereas the dehydration takes twice as long. Thus, despite theirusefulness as a reagent to promote hydrolysis and other reactions, thepreparation of concentrated aqueous solutions of γ-hydroxybutyric acidsalts is inevitably accompanied by the generation of EDCAM byproducts.

On the other hand, Japanese Patent Examined Publication Nos. Sho 64-9299and Sho 64-9300 each disclose a production method for2,2,2-trifluoromethanol, in which a γ-hydroxybutyric acid salt isreacted with 1,1,1-trifluoro-2-chloroethane in the presence ofγ-butyrolactone that serves as an aprotic polar solvent. What is notableabout this process is that the γ-butyrolactone, aside from reacting withthe alkali metal hydroxide or carbonate to form a γ-hydroxybutyric acidsalt as a raw material, serves as a solvent. Not only is the resultingγ-hydroxybutyric acid salt used to directly generate the desired2,2,2-trifluoroethanol, but it is also converted to γ-butyrolactoneafter the reaction and can thus be recycled. For these reasons, theprocess is highly advantageous.

To date, production of 2,2,2-trifluoroethanol has required theγ-hydroxybutyric acid salts produced by the above-described process. Theresultant 2,2,2-trifluoroethanol is separated from the reaction mixtureby distillation, and the solution remaining in a still afterdistillation is recycled as an aprotic polar solvent containingγ-butyrolactone. The recycle process involves separating the saltbyproduct from the still residue. This separation step has posed manyproblems. Specifically, the residual solution often becomes excessivelyviscous and organic materials and solvents may stick to the saltbyproduct, making it difficult to separate the salt byproduct byfiltration. As a result, a significant solvent loss may occur and thecrystallized salt byproduct may form large clumps together with organicmaterials. In addition, the salt byproducts so produced are oftenunsuitable for use as fertilizers and may result in increased amounts ofwaste material. Each of these problems is critical to an industrialprocess and must be eliminated.

DISCLOSURE OF THE INVENTION

In an effort to eliminate the above-described problems of the currentproduction process of 2,2,2-trifluoroethanol, the present inventorsfirst sought the causes of these problems and concluded that EDCA andEDCAM were the major factors. Specifically, the present inventors foundthat these byproducts are mostly generated during the production ofγ-hydroxybutyric acid salt and gradually accumulate as theγ-butyrolactone solvent is repeatedly recycled as an aprotic polarsolvent, thereby causing the aforementioned problems.

Thus, the present inventors devoted much effort to finding a way tominimize the generation of EDCA and EDCAM and found that this can beachieved by carrying out the production process of γ-hydroxybutyric acidsalt under particular conditions. The present inventors also conductedstudies to develop a technique for effectively removing/separating theEDCA and EDCAM byproducts from the collected γ-butyrolactone and foundthat this can be done by subjecting the γ-butyrolactone to two-layerseparation under particular conditions. Once depleted of the EDCA andEDCAM byproducts, the γ-butyrolactone can be reused in subsequentprocesses.

Accordingly, a first objective of the present invention concerns amethod for producing 2,2,2-trifluoroethanol in which a γ-hydroxybutyricacid salt is reacted with 1,1,1-trifluoro-2-chloroethane in an aproticpolar solvent to generate 2,2,2-trifluoroethanol. Such an objective isachieved by providing a production method that leads to increased yieldsof 2,2,2-trifluoroethanol, facilitates the separation of salt byproductsand allows the recycling of an aprotic polar solvent.

A second objective of the present invention is to provide a method forproducing a γ-hydroxybutyric acid salt containing a reduced amount ofEDCA. Such a γ-hydroxybutyric acid salt is suitable for use as amaterial for the production of 2,2,2-trifluoroethanol.

A third objective of the present invention is to provide a method forproducing 2,2,2-trifluoroethanol that allows γ-butyrolactone to berecycled for industrial use. Specifically, γ-butyrolactone to serve bothas a reactant and a solvent in the production of 2,2,2-trifluoroethanolis collected and is depleted of EDCA by allowing it to separate into twolayers.

The present inventors have found that the flaws of conventionalproduction processes of 2,2,2-trifluoroethanol are caused by thepresence of EDCA and EDCAM, which are mostly generated during theproduction of γ-hydroxybutyric acid salt. The inventors have also foundthat these byproducts accumulate through repeated use of theγ-butyrolactone solvent to bring about the aforementioned problems. Thepresent inventors have further found that the generation of EDCA andEDCAM can be minimized by carrying out the production process ofγ-hydroxybutyric acid salt under particular conditions and that the EDCAand EDCAM byproducts can be removed from the collected γ-butyrolactoneby subjecting the γ-butyrolactone to a two-layer separation processunder particular conditions. Once depleted of the EDCA and EDCAMbyproducts, the γ-butyrolactone can be reused in subsequent processes.These findings ultimately led the present inventors to devise theinvention.

Accordingly, a first invention concerns a method for producing2,2,2-trifluoroethanol in which 1,1,1-trifluoro-1-chloroethane isreacted with a γ-hydroxybutyric acid salt-material system containing anaprotic polar solvent and a γ-hydroxybutyric acid salt to generate2,2,2-trifluoroethanol. This method is characterized in that theγ-hydroxybutyric acid salt-material system contains no more than 6 wt %of 4,4′-oxybis(butyric acid).

A second invention concerns the first invention and is characterized inthat a solution remaining in a still after 2,2,2-trifluoroethanol hasbeen removed by distillation from a reaction mixture is reused as theaprotic polar solvent. The reaction mixture is one that results afterγ-hydroxybutyric acid salt has been reacted with1,1,1-trifluoro-2-chloroethane in the aprotic polar solvent.

A third invention concerns the first or the second invention and ischaracterized in that the γ-hydroxybutyric acid salt-material systemcomprises a γ-hydroxybutyric acid salt prepared by reacting, in theaprotic polar solvent, γ-butyrolactone with one or two or more selectedfrom the group consisting of an alkali metal hydroxide, an alkali metalcarbonate, an alkaline earth metal hydroxide and an alkaline earth metalcarbonate. The γ-hydroxybutyric acid salt is obtained by dehydrating,during or after the reaction, the reaction mixture to a waterconcentration of 0.2 to 8 wt % at a temperature of 170° C. or below.

A fourth invention concerns the first, the second or the third inventionand is characterized in that the aprotic polar solvent isγ-butyrolactone.

A fifth invention concerns the third invention and is characterized inthat the alkali metal is potassium.

A sixth invention concerns the third, the fourth or the fifth inventionand is characterized in that the dehydration is achieved byreduced-pressure distillation carried out at 150° C. or below.

A seventh invention concerns the third, the fourth, the fifth or thesixth invention and is characterized in that the dehydration iscompleted within a time period of 15 hours or less.

An eighth invention concerns a method for producing a γ-hydroxybutyricacid salt-material system, in which γ-butyrolactone is reacted in anaprotic polar solvent with one or two or more selected from the groupconsisting of an alkali metal hydroxide, an alkali metal carbonate, analkaline earth metal hydroxide and an alkaline earth metal carbonate.This method is characterized in that the reaction mixture is dehydrated,during or after the reaction, to a water concentration of 0.2 to 8 wt %at a temperature of 170° C. or below.

A ninth invention concerns the eighth invention and is characterized inthat the aprotic polar solvent is γ-butyrolactone.

A tenth invention concerns the eighth invention and is characterized inthat the alkali metal is potassium.

An eleventh invention concerns the eighth, the ninth or the tenthinvention and is characterized in that the dehydration is achieved byreduced-pressure distillation carried out at 150° C. or below.

A twelfth invention concerns the eighth, the ninth, the tenth, or theeleventh invention and is characterized in that the dehydration iscompleted within a time period of 15 hours or less.

A thirteenth invention concerns a method for producing2,2,2-trifluoroethanol characterized in that the γ-hydroxybutyric acidsalt-material system produced by the method according to the eighth, theninth, the tenth, the eleventh, or the twelfth invention is reacted with1,1,1-trifluoro-2-chloroethane.

A fourteenth invention concerns a method for producing2,2,2-trifluoroethanol in which 1,1,1-trifluoro-2-chloroethane isreacted with a γ-hydroxybutyric acid salt-material system comprisingγ-butyrolactone and potassium γ-hydroxybutyrate to generate2,2,2-trifluoroethanol. The method comprises the steps of:

reacting the γ-hydroxybutyric acid salt-material system with1,1,1-trifluoro-2-chloroethane to obtain a reaction mixture;

separating 2,2,2-trifluoroethanol by distillation from the reactionmixture to obtain a solution in a still,

removing potassium chloride byproducts from the still solution to obtaina solvent;

removing 4,4′-oxybis(butyric acid) by allowing the solution to stand toseparate it into two layers; and

recycling the collected solution as a material for potassiumγ-hydroxybutyrate and/or the γ-butyrolactone of the γ-hydroxybutyricacid salt-material system.

A fifteenth invention concerns the fourteenth invention and ischaracterized in that the collected solution contains no more than 6 wt% of 4,4′-oxybis(butyric acid).

A sixteenth invention concerns the fourteenth or the fifteenth inventionand is characterized in that the removal of 4,4′-oxybis(butyric acid) bythe two-layer separation is carried out at a temperature of 0° C. to 50°C.

A seventeenth invention concerns the fourteenth, the fifteenth or thesixteenth invention and is characterized in that the solvent is allowedto stand for at least one hour.

An eighteenth invention concerns the fourteenth, the fifteenth, thesixteenth or the seventeenth invention and is characterized in that theγ-hydroxybutyric acid salt-material system comprises a reaction mixtureobtained by mixing the purified collected γ-butyrolactone with anaqueous solution of potassium hydroxide and subsequently dehydrating themixture.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention concerns a method for producing2,2,2-trifluoroethanol in which 2,2,2-trifluoroethanol is produced byreacting 1,1,1-trifluoro-2-chloroethane with a γ-hydroxybutyric acidsalt-material system containing an aprotic polar solvent and aγ-hydroxybutyric acid salt. The method is characterized in that theγ-hydroxybutyric acid salt-material system used contains no more than 6wt % of EDCA. The use of such material system eliminates theabove-described problems, namely, the organic materials and solventssticking to the salt byproducts, which makes it difficult to separatethe salt byproducts by filtration and results in a significant solventloss; the salt byproduct crystals forming large clumps together withorganic materials; the salt byproducts becoming unsuitable for use asfertilizers; or the amount of waste material being increased.

To prepare the γ-hydroxybutyric acid salt-material system of the presentinvention, which advantageously contains no more than 6 wt % of EDCA,one, two, or more selected from alkali metal hydroxides, alkali metalcarbonates, alkaline earth metal hydroxides, and alkaline earth metalcarbonates are reacted with γ-butyrolactone in an aprotic polar solventand, during or after the reaction, water is removed from the reactionmixture at a temperature of 170° C. or below to a water concentration of0.2 to 8 wt %.

As used herein, the term “EDCA content” is the amount defined by thefollowing equation:EDCA content (%)=EDCA(g)×100/(aprotic polar solvent(g)+γ-hydroxybutyricacid salt(g)+EDCA(g)+water(g))  (1)** When EDCAM is contained in the γ-hydroxybutyric acid salt-materialsystem, the amount of EDCAM is converted to the amount of EDCA.

The term “γ-hydroxybutyric acid salt” as used herein refers to an alkalimetal salt or an alkaline earth metal salt of γ-hydroxybutyric acid.

2,2,2-trifluoroethanol can be readily prepared in high yield by reactingthe γ-hydroxybutyric acid salt-material system prepared in theabove-described manner with 1,1,1-trifluoro-2-chloroethane in thepresence of an aprotic polar solvent. The desired 2,2,2-trifluoroethanolis then removed from the resulting reaction mixture by distillation orother proper separation techniques. By simply removing the saltbyproducts from the aprotic solution remaining in a still, the residualsolution can be reused as the aprotic polar solvent without furtherpurification. In this manner, 2,2,2-trifluoroethanol can be obtained inhigh yield while the EDCA concentration in the aprotic polar solvent canbe maintained at 6 wt % or lower for a prolonged time through repeateduse of the solvent under the above-described condition.

When γ-butyrolactone is used as the aprotic polar solvent in the presentinvention and it is desired to maintain the EDCA concentration at 6 wt %or lower for an extended period of time through repeated use of thesolvent, 1,1,1-trifluoro-2-chloroethane is reacted with theγ-hydroxybutyric acid salt material-system, which containsγ-butyrolactone along with potassium γ-hydroxybutyrate, and2,2,2-trifluoroethanol is separated from the reaction mixture bydistillation. The potassium chloride byproduct is then removed from thesolution remaining in the still and the residual solvent is allowed tostand to separate and remove the EDCA and/or EDCAM by two-layerseparation. The remaining γ-butyrolactone solution can then be recycledas a material for the potassium γ-hydroxybutyrate and/or in theγ-hydroxybutyric acid salt-material system.

In this manner, increases in the viscosity of the solvent can beavoided, as can the sticking of substantial amounts of organic materialsto the salt byproduct and the significant loss of the solvent. Inaddition, this method does not result in significant amounts of wastematerial produced or the salt byproduct crystals forming large clumps,thus facilitating the filtration process. Furthermore, the saltbyproducts formed by this method are suitable for use as fertilizers.

The present invention will now be described in further detail.

The aprotic polar solvents for use in the present invention includeγ-butyrolactone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone,sulfolane, dimethylsulfoxide, dimethylformamide, and dimethylacetamide.Of these, particularly preferred are γ-butyrolactone,N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and sulfolane,with γ-butyrolactone being most preferred. γ-butyrolactone serves as anaprotic polar solvent and as a reaction reagent, acting as so-called areaction solvent. When necessary, these solvents may be usedindividually or as a mixed solvent consisting of one or more solvents.The aprotic polar solvent may be a commercially available product, or itmay be a solvent recycled after used in the production of2,2,2-trifluoroethanol and depleted of the salt byproducts. The recycledsolvent may be used unpurified.

If γ-butyrolactone is used as the aprotic polar solvent, the solvent canbe recycled for an even longer period. In this respect, γ-butyrolactoneincludes what is obtained after the solvent has been used in theproduction of 2,2,2-trifluoroethanol and has then been depleted of thesalt byproducts. The γ-butyrolactone may be used without furtherprocessing or it may be a solution collected after purified in apurification process, which will be described later. When necessary, acommercially available product may be added as desired. Theγ-butyrolactone serves not only as a solvent during the reaction ofγ-hydroxybutyric acid salt-material system with1,1,1-trifluoro-2-chloroethane to generate 2,2,2-trifluoroethanol butalso as a starting material and/or a solvent for the production ofpotassium γ-hydroxybutyrate. For this reason, it is preferred that theγ-butyrolactone contains no more than 6 wt % of EDCA. If the amount ofEDCA in the γ-butyrolactone exceeds 6 wt % when γ-butyrolactone is toserve as the starting material for the production of γ-hydroxybutyricacid salt, then some of the alkali added is consumed by EDCA, thusmaking it difficult to obtain a desired amount of the γ-hydroxybutyricacid salt. On the other hand, if the amount of EDCA exceeds 6 wt % whenγ-butyrolactone is to serve as the solvent, then the aforementionedproblems of the process will result. In this case, a commerciallyavailable product is used as the γ-butyrolactone in the first round ofthe reaction. The γ-butyrolactone is recycled in the second andsucceeding rounds and used without further processing or after purifiedin a purification process, which will be described later.

In the present invention, the starting materials for the production ofγ-hydroxybutyric acid salt may include one or two or more inorganiccompounds selected from alkali metal hydroxides, alkali metalcarbonates, alkaline earth metal hydroxides, and alkaline earth metalcarbonates. Examples of such compounds include hydroxides and carbonatesof lithium, sodium, potassium, and calcium. Hydroxides and carbonates ofpotassium are particularly preferred. The potassium hydroxides may beprovided in the form of an aqueous solution of a commercially availablepotassium hydroxide or a commercially available aqueous solution ofpotassium hydroxide. The concentration of the aqueous solution ofpotassium hydroxide is preferably in the range of 10 to 48 wt % althoughsuch a solution may have any concentration. The potassium carbonate maybe provided in the form of potassium carbonate and/or potassiumbicarbonate. Commercially available potassium carbonate products may beused without any processing. The potassium carbonate provided in theform of powder may also be used by dissolving it in water, if necessary.

According to the present invention, the above-described materials areused to prepare the γ-hydroxybutyric acid salt-material system. How thiscan be done will now be explained by taking an example in whichγ-butyrolactone is used along with a 48% aqueous solution of potassiumhydroxide. Predetermined amounts of an aprotic polar solvent andγ-butyrolactone to serve as a starting material are placed in a reactorequipped with a thermometer, a stirrer, dropping equipment, and apressure reducing device. While the mixture is constantly stirred, apredetermined amount of the aqueous solution of potassium hydroxide isdelivered dropwise from the dropping equipment to produce potassiumγ-hydroxybutyrate. Since the reaction is an exothermic reaction thatproceeds quantitatively, water is added as desired for cooling. Theamount of the potassium hydroxide added is adjusted so that the amountof the resulting potassium γ-hydroxybutyrate is preferably no more than30 wt % with respect to the aprotic polar solvent. The potassiumγ-hydroxybutyrate, when generated in an amount greater than 30 wt %, canmake the reaction mixture excessively viscous and can thereby make thestirring of the mixture and, thus, the dehydration process difficult.

The reaction of γ-butyrolactone with potassium hydroxide is shown by thefollowing chemical equation:

[Chemical Equation]

According to the present invention, the aprotic polar solvent containingpotassium γ-hydroxybutyrate is then dehydrated by heating. Thedehydration is done by atmospheric distillation or reduced-pressuredistillation at a temperature of 170° C. or below, preferably 150° C. orbelow. In the case of reduced-pressure distillation, pressure is reducedto for example about 0.07 to 0.67 MPa. Preferably, the dehydrationprocess is carried out within a time period not exceeding 15 hours andis continued until the water content in the aprotic polar solvent isfrom 0.2 to 8 wt %. The process exceeding 15 hours tends to result in asubstantial amount of EDCAM generated. Also, the water content of theaprotic polar solvent that exceeds 8 wt % may lead to a significantdecrease in the rate of the subsequent hydrolysis of1,1,1-trifluoro-2-chloroethane and is thus unfavorable.

According to the present invention, once dehydrated, the potassiumγ-hydroxybutyrate-containing aprotic polar solvent is transferred to apressurized container, in which it is reacted with1,1,1-trifluoro-2-chloroethane to produce 2,2,2-trifluoroethanol.1,1,1-trifluoro-2-chloroethane used in this process may be obtained by aknown method, for example, by using trichloroethylene with hydrofluoricacid in the presence of a catalyst. Preferably,1,1,1-trifluoro-2-chloroethane has a 98% or higher purity although itmay have any suitable purity. The 1,1,1-trifluoro-2-chloroethane maycontain 1,1,2-tetrafluoroethane (134a) or any other impurity that is notinvolved in the present reaction.

According to present invention, the procedures and conditions for thereaction can be properly selected as described in examples in thisdescription. For example, the above-described potassiumγ-hydroxybutyrate-containing aprotic polar solvent is placed in apressurized container along with 1,1,1-trifluoro-2-chloroethane and thereaction is allowed to proceed at 180 to 220° C. for 3 to 8 hours untilcompletion while the reaction mixture is constantly stirred. After theunreacted 1,1,1-trifluoro-2-chloroethane has been purged, the reactionmixture is collected and is then distilled. As a result, the desired2,2,2-trifluoroethanol product is separated. Meanwhile, the residueremaining in the still after distillation takes the form of a slurry andcomprises a γ-butyrolactone-containing aprotic polar solution and apotassium chloride byproduct. The potassium chloride is separated as asolid by filtration, centrifugation or other solid-liquid separationtechniques. The γ-butyrolactone-containing aprotic polar solutioncollected in the solid-liquid separation process is then recycled,without further processing, to serve as the solvent or the material ofpotassium γ-hydroxybutyrate in the next round of the reaction. Afterseparation, the aprotic polar solution contains no more than 6 wt % ofEDCA. Should the amount of EDCA exceed 6 wt %, significant problems mayarise, such as a decrease in the yield of 2,2,2-trifluoroethanol; anincreased viscosity, which makes the filtration process difficult; asignificant amount of organic materials sticking to the salt byproducts;a substantial solvent loss; an increased amount of waste material; orthe salt byproduct crystals forming clumps.

According to the present invention, when the aprotic nonpolar solvent isγ-butyrolactone and it is desired to recycle the solvent for an extendedperiod of time, the γ-butyrolactone solvent, collected in thesolid-liquid separation step as described above, is left to stand toallow it to separate into two layers for purification. This process doesnot require special techniques or apparatuses and can be done by simplyallowing the solvent to stand undisturbed. This allows the solvent toseparate into two layers with the top γ-butyrolactone layer containing 6wt % or less EDCA. This top layer can be collected and recycled.

According to the present invention, the process of leaving the solventfor separating it into two layers is preferably carried out at atemperature of 0° C. to 50° C., and more preferably at a temperature of0° C. to 40° C. If the process is carried out at a temperature of above50° C., not only does it take a substantial amount of time for thesolvent to separate into two layers, but the EDCA content in the topγ-butyrolactone layer or the collected solution is also somewhatincreased. In comparison, if the solvent is to be cooled to below 0° C.,a large facility is required.

According to the present invention, while the solvent may be left tostand for any time length to allow it to separate into two layers, itneeds to be left for at least 1 hour. When left for too short a timeperiod, the solvent does not completely separate into two layers and theEDCA content in the top γ-butyrolactone layer or the collected solutionis somewhat increased. According to the present invention, theabove-described purification process may be carried out as frequently asdesired: the solvent may be left to stand for removing EDCA each timethe solvent is collected or after repeatedly used in the reaction.

According to the present invention, the collected solvent, which hasbeen purified by removing EDCA and/or EDCAM in the two-layer separationprocess as described above, is recycled as a solvent for use in theproduction of 2,2,2-trifluoroethanol and/or as a material for2,2,2-trifluoroethanol. As a result, no significant problems regardingthe process arise as a result of the repetitive use of theγ-butyrolactone solvent to serve as a solvent and/or a material in theindustrial production of 2,2,2-trifluoroethanol. In this regard, theγ-butyrolactone solvent can be recycled without any special processing.Specifically, many of the problems associated with the conventionalprocess have been eliminated, such as the solution becoming excessivelyviscous; significant amounts of organic materials adhering to the saltbyproducts; significant amounts of solvent being lost; waste materialsproduced in large quantity; the salt byproduct crystals forming clumps,making filtration difficult. The problem of the salt byproducts becomingunsuitable for use as fertilizers is also avoided. According to thepresent invention, the collected solvent can be purified and recycled asmany times as desired.

The reaction of potassium γ-hydroxybutyrate with1,1,1-trifluoro-2-chloroethane is shown by the following chemicalequations:

[Chemical Equation]

EXAMPLES

The present invention will now be described with reference to Examples,which are provided by way of example only and are not intended to limitthe scope of the invention in any way.

Example 1

650 g (7.55 mol) γ-butyrolactone was placed in a 1000 ml flask equippedwith a reduced pressure distillation apparatus, a thermometer, astirrer, and a dropping funnel. 102 g of a 48% aqueous solution ofpotassium hydroxide (0.873 mol potassium hydroxide) was poured in thedropping funnel and was added dropwise approximately over 40 minuteswhile being stirred. The addition of the solution caused the reactionmixture to gradually generate heat and the internal temperature rose toapproximately 50° C. The pressure of the system was reduced to 0.4 MPaand the reaction mixture was distilled for 12 hours to remove waterwhile it was gradually heated to 145° C.

The resulting γ-butyrolactone solution contained 17.2 wt % potassiumγ-hydroxybutyrate. A portion of this solution was neutralized withhydrochloric acid and was subjected to HPLC analysis. The results of theanalysis indicated that no EDCA (4,4′-oxybis(butyric acid)) wasgenerated. The water content of the γ-butyrolactone solution wasanalyzed by Karl Fischer technique and was determined to be 3.4 wt %.

Example 2

Potassium γ-hydroxybutyrate was synthesized in the same manner as inExample 1, except that water was distilled out at 165° C. and thepressure of the system was reduced to 0.8 MPa.

The resulting γ-butyrolactone solution contained 17.0 wt % potassiumγ-hydroxybutyrate. A portion of this solution was neutralized withhydrochloric acid and was subjected to HPLC analysis. The results of theanalysis indicated that 0.2 wt % EDCA (4,4′-oxybis(butyric acid)) wasgenerated. The water content of the γ-butyrolactone solution wasanalyzed by Karl Fischer technique and was determined to be 3.3 wt %.

Example 3

Potassium γ-hydroxybutyrate was synthesized in the same manner as inExample 1, except that the distillation was continued for 18 hours.

The resulting γ-butyrolactone solution contained 16.6 wt % potassiumγ-hydroxybutyrate. A portion of this solution was neutralized withhydrochloric acid and was subjected to HPLC analysis. The results of theanalysis indicated that 0.8 wt % EDCA (4,4′-oxybis(butyric acid)) wasgenerated. The water content of the γ-butyrolactone solution wasanalyzed by Karl Fischer technique and was determined to be 3.5 wt %.

Example 4

Potassium γ-hydroxybutyrate was synthesized in the same manner as inExample 1, except that the amount of the 48% aqueous solution ofpotassium hydroxide used was 158 g (1.35 mol potassium hydroxide).

The addition of potassium hydroxide caused the internal temperature torise to approximately 70° C. The resulting γ-butyrolactone solutioncontained 25.2 wt % potassium γ-hydroxybutyrate. A portion of thissolution was neutralized with hydrochloric acid and was subjected toHPLC analysis. The results of the analysis indicated that 0.3 wt % EDCA(4,4′-oxybis(butyric acid)) was generated. The water content of theγ-butyrolactone solution was analyzed by Karl Fischer technique and wasdetermined to be 3.7 wt %.

Example 5

Potassium γ-hydroxybutyrate was synthesized in the same manner as inExample 1, except that 521 g N-methylpyrrolidone and 129 gγ-butyrolactone (1.80 mol) were used in place of γ-butyrolactone.

The resulting γ-butyrolactone solution contained 17.0 wt % potassiumγ-hydroxybutyrate. A portion of this solution was neutralized withhydrochloric acid and was subjected to HPLC analysis. The results of theanalysis indicated that no EDCA (4,4′-oxybis(butyric acid)) wasgenerated. The water content of the γ-butyrolactone solution wasanalyzed by Karl Fischer technique and was determined to be 4.2 wt %.

Example 6

700 g of the potassium γ-hydroxybutyrate solution obtained in Example 1were transferred to a 1000 mL SUS316 autoclave equipped with a magneticstirrer. The autoclave was sealed and the atmosphere inside was replacedwith nitrogen three times. 150 g (1.27 mol) of1,1,1-trifluoro-2-chloroethane were added from a pressurized container.The mixture was heated to 200° C. while being stirred and the reactionwas allowed to proceed for 6 hours under a pressure of 1.5 MPa.Subsequently, the autoclave was cooled to 150° C. and a trap cooled toapproximately 0° C. was attached to the opening of the autoclave. Thepressure inside was then slowly reduced to purge the unreacted1,1,1-trifluoro-2-chloroethane. The resulting 2,2,2-trifluoroethanolproduct was completely removed by distillation while the reactionmixture was stirred by the magnetic stirrer. The yield of the productwas 96% with respect to potassium γ-hydroxybutyrate. The autoclave wasthen allowed to cool to room temperature to collect in a still asolution containing γ-butyrolactone and potassium chloride byproduct.The still solution was then filtered through a G3 glass filter toseparate the potassium chloride byproduct. As a result, a light brownγ-butyrolactone solvent having a normal viscosity was obtained. The saltbyproduct was readily separated by filtration and was obtained as awhite powder.

Example 7

Using the γ-butyrolactone-containing still solution obtained in Example6, the procedures of Example 1 and Example 6 were repeated 6 times.After each batch process, 2,2,2-trifluoroethanol was obtained at 94 to98% yield (with respect to potassium hydroxide). After each round of therepeating process, a few grams of γ-butyrolactone were supplied tocompensate for the material lost by the sampling and each procedure.After 6 rounds, the still solution turned dark brown but stillmaintained normal viscosity. The salt byproduct was obtained as aslightly yellow brownish powder and was readily separated by filtrationthrough G3 glass filter. A portion of this solution was neutralized withhydrochloric acid and was subjected to HPLC analysis. The results of theanalysis indicated that the solution contained 1.5% EDCA(4,4′-oxybis(butyric acid)).

Example 8

A γ-butyrolactone solvent containing a significant amount of EDCA (EDCAcontent=8.0 wt %) was obtained in the manner described in ComparativeExample 2, which will be described later. A portion of the solvent wasallowed to stand at 50° C. for 30 hours to separate it into two layers.The top layer, the γ-butyrolactone solution layer to be collected,contained 3.9 wt % of EDCA.

The top layer was collected and was used to produce2,2,2-trifluoroethanol. Specifically, 150 g γ-butyrolactone (1.74 molassuming it consists sorely of γ-butyrolactone) was placed in a 300 mlflask equipped with a reduced pressure distillation apparatus, athermometer, a stirrer, and a dropping funnel. 23.5 g of a 48% aqueoussolution of potassium hydroxide (0.20 mol potassium hydroxide) werepoured into the dropping funnel and were added dropwise overapproximately 40 minutes while being stirred. The addition of thesolution caused the reaction mixture to gradually generate heat and theinternal temperature rose to approximately 50° C. The pressure of thesystem was reduced to 0.4 MPa and the reaction mixture was distilled for12 hours to remove water while it was gradually heated to 145° C. Theresulting solution of potassium γ-hydroxybutyrate contained 4.4 wt %EDCA and 3.6 wt % water. 165 g of the potassium γ-hydroxybutyratesolution were transferred to a 300 ml SUS316 autoclave equipped with amagnetic stirrer. The autoclave was sealed and the atmosphere inside wasreplaced with nitrogen three times. 35.3 g (0.30 mol) of1,1,1-trifluoro-2-chloroethane were added from a pressurized container.The mixture was heated to 200° C. while being stirred and the reactionwas allowed to proceed for 6 hours under a pressure of 1.5 MPa.Subsequently, the autoclave was cooled to 150° C. and a trap cooled toapproximately 0° C. was attached to the opening of the autoclave. Thepressure inside was then slowly reduced to purge the unreacted1,1,1-trifluoro-2-chloroethane. The resulting 2,2,2-trifluoroethanolproduct was completely removed by distillation while the reactionmixture was stirred by the magnetic stirrer. The yield of the productwas 95% with respect to potassium γ-hydroxybutyrate. The autoclave wasthen allowed to cool to room temperature to collect in a still asolution containing γ-butyrolactone and potassium chloride byproduct.The still solution was then filtered through a G3 glass filter toseparate the potassium chloride byproduct. As a result, a dark brownγ-butyrolactone solvent was collected. Containing 4.8 wt % EDCA, thesolvent had a normal viscosity and was of the nature that did not causeany process-related problem, such as filtration taking too long.

Example 9

Purification was carried out in the same manner as in Example 8, exceptthat the γ-butyrolactone solvent was allowed to stand at 25° C. for 15hours to separate it in two layers. The top layer, the γ-butyrolactonesolution layer to be collected, contained 3.3 wt % of EDCA.

Example 10

Purification was carried out in the same manner as in Example 8, exceptthat the γ-butyrolactone solvent was allowed to stand at 0° C. for 1hour to separate it in two layers. The top layer, the γ-butyrolactonesolution layer to be collected, contained 3.1 wt % of EDCA.

Example 11

To purify the collected γ-butyrolactone, 2,2,2-trifluoroethanol wasproduced in a 5 m³ γ-butyrolactone-purification tank with a top outlet.After the reaction had been completed, the potassium chloride byproductwas separated by filtration and the collected γ-butyrolactone solventwas reused to serve both as material and solvent for the reactionwithout further processing. A commercially available γ-butyrolactoneproduct was supplied in an amount required to compensate for theγ-butyrolactone lost along with the potassium chloride byproduct. After3 months of repeating this cycle, the EDCA content in the collectedγ-butyrolactone solvent reached 5.9%. At this stage, the collectedγ-butyrolactone solvent was placed in the purification tank and wasallowed to stand at 25° C. for 10 hours for purification. As a result,the solvent separated into two layers and the EDCA content in the toplayer, the γ-butyrolactone solvent layer to be collected, was decreasedto 2.7%. In contrast, the bottom layer of the γ-butyrolactone solutioncontained significant amounts of water, KCl, and EDCA.

Comparative Example 1

A potassium γ-hydroxybutyrate solution was prepared in the same manneras in Example 1, except that the distillation to remove water wascarried out at 190 to 200° C. for 20 hours under atmospheric pressure.The resulting γ-butyrolactone solution contained 11.2 wt % potassiumγ-hydroxybutyrate.

A portion of this solution was neutralized with hydrochloric acid andwas subjected to HPLC analysis. The results of the analysis indicatedthat 7 wt % EDCA (4,4′-oxybis(butyric acid)) was generated. The watercontent of the γ-butyrolactone solution was analyzed by Karl Fischertechnique and was determined to be 4.5%.

Comparative Example 2

Using the potassium γ-hydroxybutyrate solution obtained in ComparativeExample 1, 2,2,2-trifluoroethanol was produced in the same manner as inExample 6. Subsequently, the same procedures as in Example 6 werefollowed to obtain a solution in a still. The yield of2,2,2-trifluoroethanol was 91%. The still solution was then filteredthrough a G3 glass filter to separate the potassium chloride byproduct.As a result, a light brown γ-butyrolactone solvent having a relativelyhigh viscosity was obtained. The salt byproduct was obtained as a whitepowder with some organic material adhering to it. The filtration of thesalt product took considerable time and was extremely difficult. Thecollected γ-butyrolactone solution contained 8.0 wt % EDCA.

Comparative Example 3

A potassium γ-hydroxybutyrate solution was synthesized in the samemanner as in Example 1, except that 242 g of a 48% aqueous solution ofpotassium hydroxide (2.00 mol potassium hydroxide) were used, that theinternal temperature was raised to 120° C., and that the distillation toremove water was carried out at 200° C. for 24 hours under atmosphericpressure. The resulting γ-butyrolactone solution contained 13.1 wt %potassium γ-hydroxybutyrate. The solution was extremely viscous and wasdifficult to stir.

A portion of this solution was neutralized with hydrochloric acid andwas subjected to HPLC analysis. The results of the analysis indicatedthat 35.8 wt % EDCA (4,4′-oxybis(butyric acid)) was generated. The watercontent of the γ-butyrolactone solution was analyzed by Karl Fischertechnique and was determined to be 6.4%.

When the γ-butyrolactone solution was used in hydrolysis, the reactionrate was low. Subsequently, the same procedures as in Example 6 werefollowed to separate 2,2,2-trifluoroethanol and obtain a still solution.The yield of 2,2,2-trifluoroethanol was 86%. No potassium salt wasseparated after one-hour filtration of the solution.

Comparative Example 4

A potassium γ-hydroxybutyrate solution was prepared in exactly the samemanner as in Example 1. The pressure of the system was reduced to 0.4MPa and the reaction mixture was distilled for 15 hours to thoroughlyremove water while it was gradually heated to 145° C. The water contentof the γ-butyrolactone solution was analyzed by Karl Fischer techniqueand was determined to be 0.1 wt %.

700 g of the potassium γ-hydroxybutyrate solution were transferred to a1000 ml SUS316 autoclave equipped with a magnetic stirrer. The autoclavewas sealed and the atmosphere inside was replaced with nitrogen threetimes. 150 g (1.27 mol) of 1,1,1-trifluoro-2-chloroethane were addedfrom a pressurized container. The mixture was heated to 200° C. whilebeing stirred and the reaction was allowed to proceed for 6 hours.Subsequently, the same procedures as in Example 6 were followed toseparate 2,2,2-trifluoroethanol and obtain a still solution. The yieldof 2,2,2-trifluoroethanol was 73%. No potassium salt was separated afterone-hour filtration of the solution.

Comparative Example 5

650 g (7.55 mol) of γ-butyrolactone and 49 g of pellets of solidpotassium hydroxide were placed in a 1000 ml SUS316 autoclave equippedwith a magnetic stirrer. The autoclave was sealed and the atmosphereinside was replaced with nitrogen three times. 150 g (1.27 mol) of1,1,1-trifluoro-2-chloroethane were added from a pressurized container.The mixture was heated to 200° C. while being stirred and the reactionwas allowed to proceed for 6 hours under a pressure of 1.5 MPa.Subsequently, the autoclave was cooled to room temperature. The pressureinside was then slowly reduced to purge the unreacted1,1,1-trifluoro-2-chloroethane. Subsequently, the same procedures as inExample 6 were followed to separate 2,2,2-trifluoroethanol and obtain astill solution. The yield of 2,2,2-trifluoroethanol was 68%. Nopotassium salt was separated after one-hour filtration of the solution.

Comparative Example 6

Potassium γ-hydroxybutyrate was synthesized in the same manner as inExample 1, except that the reaction mixture was distilled for 8 hours toremove water. A portion of the potassium γ-hydroxybutyrate was taken andwas analyzed for the water content by Karl Fischer technique. Theresults of the analysis indicated that the reaction mixture contained10.1 wt % water.

Using 700 g of the potassium γ-hydroxybutyrate solution, the reactionwas carried out in the same manner as in Example 6. After the reaction,114 g of unreacted 1,1,1-trifluoro-2-chloroethane were collected,indicating that only 27% of the reactant (as determined by the amount ofpotassium hydroxide) had reacted.

Comparative Example 7

Purification was carried out in exactly the same manner as in Example10, except that the γ-butyrolactone solvent was allowed to stand for 30minutes. The solvent did not separate into two layers and thus could notbe purified. Using the resulting solvent without further processing,2,2,2-trifluoroethanol was produced in exactly the same manner as inExample 8. As a result, the yield of 2,2,2-trifluoroethanol was 78%. Thepotassium chloride byproduct was separated by filtration through a G3glass filter. As a result, a dark brown γ-butyrolactone having arelatively high viscosity was obtained. The salt byproduct was obtainedas a light yellow powder with some organic material adhering to it. Thefiltration of the salt product took considerable time and was difficult.According to analytical result, the separated γ-butyrolactone solutioncontained 8.7 wt % EDCA.

Comparative Example 8

Purification was carried out in exactly the same manner as in Example 9,except that the γ-butyrolactone solvent was allowed to stand at 60° C.for two layer separation. However, the solvent did not separate into twolayers and thus could not be purified.

Comparative Example 9

Purification was carried out in exactly the same manner as in Example 9,except that the γ-butyrolactone solvent was allowed to stand for 30minutes for two layer separation. However, the solvent did not separateinto two layers and thus could not be purified.

INDUSTRIAL APPLICABILITY

The present inventions according to claim 1 through 7 increase the yieldof 2,2,2-trifluoroethanol, facilitates the separation of the saltbyproducts and allows the recycling of the collected aprotic polarsolvent.

The present inventions according to claim 8 through 12 allows theproduction of a γ-hydroxybutyric acid salt containing decreased amountsof EDCA. Such a γ-hydroxybutyric acid salt is better suited for theproduction of 2,2,2-trifluoroethanol.

When used in the hydrolysis of 1,1,1-trifluoroethyl chloride, aγ-hydroxybutyric acid salt produced according to the invention of claim13 facilitates the separation of salt byproducts after2,2,2-trifluoroethanol has been collected and allows the remainingsolution to be recycled without any processings. As a result, the lossof the solvent during the process is reduced and the separation of thesalt byproducts has become easy. In addition, the salt byproducts can beused in fertilizers.

The inventions according to claims 14 through 18 allow the removal ofEDCA and/or EDCAM byproducts from the γ-butyrolactone to serve both as areactant and a solvent and allow the collected γ-butyrolactone to berecycled as many times as desired. Specifically, the γ-butyrolactonecollected after used in the hydrolysis of 1,1,1-trifluoroethylchlorideis purified by the two-layer separation. As a result, the loss of thesolvent during the process is reduced and the separation of the saltbyproducts has become easy. In addition, the salt byproducts can be usedin fertilizers.

1. A method for producing 2,2,2-trifluoroethanol comprising reacting1,1,1-trifluoro-2-chloroethane with a γ-hydroxybutyric acidsalt-material system comprising an aprotic polar solvent and aγ-hydroxybutyric acid salt to generate 2,2,2-trifluoroethanol, whereinthe γ-hydroxybutyric acid salt-material system comprises no more than 6wt % of 4,4′-oxybis(butyric acid).
 2. The method for producing2,2,2-trifluoroethanol according to claim 1, wherein the reaction of theγ-hydroxybutyric acid salt-material system and1,1,1-trifluoro-2-chloroethane results in a reaction mixture comprising2,2,2-tri-fluoroethanol, and wherein a solution remaining in a stillafter 2,2,2-trifluoroethanol has been removed by distillation from thereaction mixture is reused as the aprotic polar solvent.
 3. The methodfor producing 2,2,2-trifluoroethanol according to claim 1, wherein theγ-hydroxybutyric acid salt-material system is prepared by reacting, inthe aprotic polar solvent, γ-butyrolactone with at least one memberselected from the group consisting of an alkali metal hydroxide, analkali metal carbonate, an alkaline earth metal hydroxide and analkaline earth metal carbonate to create a reaction mixture, anddehydrating the reaction mixture, during or after the reaction, to awater concentration of 0.2 to 8 wt % at a temperature of 170° C. orbelow.
 4. The method for producing 2,2,2-trifluoroethanol according toclaim 1, wherein the aprotic polar solvent is γ-butyrolactone.
 5. Themethod for producing 2,2,2-trifluoroethanol according to claim 3,wherein the alkali metal is potassium.
 6. The method for producing2,2,2-trifluoroethanol according to claim 3, wherein the dehydration isachieved by reduced-pressure distillation carried out at 150° C. orbelow.
 7. The method for producing 2,2,2-trifluoroethanol according toclaim 3, wherein the dehydration is completed within a time period of 15hours or less.
 8. A method for producing a γ-hydroxybutyric acidsalt-material system, comprising reacting γ-butyrolactone, in an aproticpolar solvent, with at least one member selected from the groupconsisting of an alkali metal hydroxide, an alkali metal carbonate, analkaline earth metal hydroxide and an alkaline earth metal carbonate tocreate a reaction mixture, and dehydrating the reaction mixture, duringor after the reaction, to a water concentration of 0.2 to 8 wt % at atemperature of 170° C. or below.
 9. The method for producing aγ-hydroxybutyric acid salt-material system according to claim 8, whereinthe aprotic polar solvent is γ-butyrolactone.
 10. The method forproducing a γ-hydroxybutyric acid salt-material system according toclaim 8, wherein the alkali metal is potassium.
 11. The method forproducing a γ-hydroxybutyric acid salt-material system according toclaim 8, wherein the dehydration is achieved by reduced-pressuredistillation carried out at 150° C. or below.
 12. The method forproducing a γ-hydroxybutyric acid salt-material system according toclaim 8, wherein the dehydration is completed within a time period of 15hours or less.
 13. A method for producing 2,2,2-trifluoroethanol,comprising reacting the γ-hydroxybutyric acid salt-material systemproduced by the method according to claim 8 with1,1,1-trifluoro-2-chloroethane.
 14. A method for producing2,2,2-trifluoroethanol comprising: reacting a γ-hydroxybutyric acidsalt-material system comprising γ-butyrolactone and potassiumγ-hydroxybutyrate with 1,1,1-trifluoro-2-chloroethane to obtain areaction mixture comprising 2,2,2-trifluororethanol; separating2,2,2-trifluoroethanol by distillation from the reaction mixture toobtain a solution comprising potassium chloride byproducts and4,4′-oxybis(butyric acid) in a still, removing potassium chloridebyproducts from the still solution to obtain a solvent; removing4,4′-oxybis(butyric acid) by allowing the solvent to stand to separateit into two layers, one of which is a solution comprisingγ-butyrolactone; collecting the resulting γ-butyrolactone solution; andrecycling the collected γ-butyrolactone solution as a material forpotassium γ-hydroxybutyrate and/or the γ-butyrolactone of theγ-hydroxybutyric acid salt-material system.
 15. The method for producing2,2,2-trifluoroethanol according to claim 14, wherein the collectedγ-butyrolactone solution contains no more than 6 wt % of4,4′-oxybis(butyric acid).
 16. The method for producing2,2,2-trifluoroethanol according to claim 14, wherein the removal of4,4′-oxybis(butyric acid) by the two-layer separation is carried out ata temperature of 0° C. to 50° C.
 17. The method for producing2,2,2-trifluoroethanol according to claim 14, wherein the solvent isallowed to stand for at least one hour.
 18. The method for producing2,2,2-trifluoroethanol according to claim 14, wherein theγ-hydroxybutyric acid salt-material system comprises a reaction mixtureobtained by mixing the collected γ-butyrolactone solution with anaqueous solution of potassium hydroxide and subsequently dehydrating themixture.
 19. The method for producing 2,2,2-trifluoroethanol accordingto claim 2, wherein the γ-hydroxybutyric acid salt-material system isprepared by reacting, in the aprotic polar solvent, γ-butyrolactone withat least one member selected from the group consisting of an alkalimetal hydroxide, an alkali metal carbonate, an alkaline earth metalhydroxide and an alkaline earth metal carbonate to create a reactionmixture, and dehydrating the reaction mixture during or after thereaction, to a water concentration of 0.2 to 8 wt % at a temperature of170° C. or below.
 20. The method for producing 2,2,2-trifluoroethanolaccording to claim 2, wherein the aprotic polar solvent isγ-butyrolactone.
 21. The method for producing 2,2,2-trifluoroethanolaccording to claim 3, wherein the aprotic polar solvent isγ-butyrolactone.
 22. The method for producing 2,2,2-trifluoroethanolaccording to claim 4, wherein the dehydration is achieved byreduced-pressure distillation carried out at 150° C. or below.
 23. Themethod for producing 2,2,2-trifluoroethanol according to claim 5,wherein the dehydration is achieved by reduced-pressure distillationcarried out at 150° C. or below.
 24. The method for producing2,2,2-trifluoroethanol according to claim 4, wherein the dehydration iscompleted within a time period of 15 hours or less.
 25. The method forproducing 2,2,2-trifluoroethanol according to claim 5, wherein thedehydration is completed within a time period of 15 hours or less. 26.The method for producing 2,2,2-trifluoroethanol according to claim 6,wherein the dehydration is completed within a time period of 15 hours orless.
 27. The method for producing a γ-hydroxybutyric acid salt-materialsystem according to claim 9, wherein the dehydration is achieved byreduced-pressure distillation carried out at 150° C. or below.
 28. Themethod for producing a γ-hydroxybutyric acid salt-material systemaccording to claim 10, wherein the dehydration is achieved byreduced-pressure distillation carried out at 150° C. or below.
 29. Themethod for producing a γ-hydroxybutyric acid salt-material systemaccording to claim 9, wherein the dehydration is completed within a timeperiod of 15 hours or less.
 30. The method for producing aγ-hydroxybutyric acid salt-material system according to claim 10,wherein the dehydration is completed within a time period of 15 hours orless.
 31. The method for producing a γ-hydroxybutyric acid salt-materialsystem according to claim 11, wherein the dehydration is completedwithin a time period of 15 hours or less.
 32. A method for producing2,2,2-trifluoroethanol, comprising reacting the γ-hydroxybutyric acidsalt-material system produced by the method according to claim 9 with1,1,1-trifluoro-2-chloroethane.
 33. A method for producing2,2,2-trifluoroethanol, comprising reacting the γ-hydroxybutyric acidsalt-material system produced by the method according to claim 10 with1,1,1-trifluoro-2-chloroethane.
 34. A method for producing2,2,2-trifluoroethanol, comprising reacting the γ-hydroxybutyric acidsalt-material system produced by the method according to claim 11 with1,1,1-trifluoro-2-chloroethane.
 35. A method for producing2,2,2-trifluoroethanol, comprising reacting the γ-hydroxybutyric acidsalt-material system produced by the method according to claim 12 with1,1,1-trifluoro-2-chloroethane.
 36. The method for producing2,2,2-trifluoroethanol according to claim 15, wherein the removal of4,4′-oxybis(butyric acid) by the two-layer separation is carried out ata temperature of 0° C. to 50° C.
 37. The method for producing2,2,2-trifluoroethanol according to claim 15, wherein the solvent isallowed to stand for at least one hour.
 38. The method for producing2,2,2-trifluoroethanol according to claim 16, wherein the solvent isallowed to stand for at least one hour.
 39. The method for producing2,2,2-trifluoroethanol according to claim 15, wherein theγ-hydroxybutyric acid salt-material system comprises a reaction mixtureobtained by mixing the collected γ-butyrolactone solution with anaqueous solution of potassium hydroxide and subsequently dehydrating themixture.
 40. The method for producing 2,2,2-trifluoroethanol accordingto claim 16, wherein the γ-hydroxybutyric acid salt-material systemcomprises a reaction mixture obtained by mixing the collectedγ-butyrolactone solution with an aqueous solution of potassium hydroxideand subsequently dehydrating the mixture.
 41. The method for producing2,2,2-trifluoroethanol according to claim 17, wherein theγ-hydroxybutyric acid salt-material system comprises a reaction mixtureobtained by mixing the collected γ-butyrolactone solution with anaqueous solution of potassium hydroxide and subsequently dehydrating themixture.